So-called Lippmann emulsions having an average grain size of less than 0.1 .mu.m (100 nm) are of particular importance for the preparation of photographic plates or films with high resolution for use in microphotography, for recording nucleophysical phenomena, for the preparation of masks in the production of microelectronic integrated circuits, for use in holography, for high density storage, etc.
In the production of microelectronic integrated circuits drawings are made, optionally on a highly enlarged scale, of the various successive masks necessary to produce one integrated circuit whereupon the drawings are reduced, if necessary in successive steps, and reproduced on a photographic plate or film material forming thereby the mask ready for use. By various photographic and and chemical steps (photo-etching of laquered plates) the images of the masks thus produced are transferred to the surface on which the integrated circuit is to be made, in order to produce the required circuit elements. In recent times several of the preliminary steps are reproduced digitally.
The photographic materials for use in the production of masks as described above should have a high resolving power and acutance and allow a correct reproduction of the dimensions of the image. Unless the dimensional reproduction is kept within the accepted tolerances the maks will be useless because it will not enable electronic components to be formed in the circuitry with the required degree of accuracy. Developments in the field of computer and telecommunication systems create the need for ever increasing packing densities on the circuit elements and therefore it has become common practice to reproduce image details e.g. lines and slits having widths even smaller than the emulsion thickness e.g. smaller than 5 .mu.m. These image details should be reproduced within the accepted width tolerances of at most 10% respective to the original width.
Old patents dealing with the type of material described above are e.g. U.S. Pat. Nos. 3,652,280, 4,148,647, 4,108,661, and DE 2002062.
Materials and corresponding processing chemicals usable in the applications as explained above are marketed by Agfa-Gevaert N.V. under the trade name MILLIMASK.
Now recently new applications for this type of material have been invented by us that pose high requirements to the material concerning resistance to mechanical and thermal deformation. This is the case when the material is used under so-called "heavy duty" circumstances such as high temperature, extreme humidity, fast changes in temperature or humidity, or high mechanical stress. Under these circumstances the conventional supports for this type of material such as glass or polyethylene terephthalate and acrylic plates behave unsatisfactory.